It is often desirable to recover metals from non-aqueous, organic solutions. In the past, this has been done by various means such as stripping the compound of the metal from the organic phase into an aqueous phase and then chemically or electrolytically depositing the metal, crystallizing the metal compound from the organic phase followed by further processing the crystals so as to deposit the metal or electrowinning, i.e., electrodepositing the metal directly from the organic phase onto a cathode placed therein.
The recovery of metals as indicated above is particularly important when metals are refined or recovered from wastes utilizing solvent extraction techniques for separating the various metals in solution. This technique is based upon the varying degree of solubility of certain metal compounds or complexes between immiscible aqueous and organic solvents under certain conditions of pH and other factors.
In the past, electrodeposition of the metal from the organic phase was generally not commercially feasible due to the fact that the organic solvent which was employed to effectuate separation was generally a poor electrolyte and hence limited the current and thus the rate of metal deposition at voltages which did not result in solvent breakdown.
I have now discovered a technique for electrodepositing metals from organic solvents which can be used efficiently and with substantially higher deposition rates than otherwise expected.